Part of viaduct to be removed six months early

By SCOTT GUTIERREZ, SEATTLEPI.COM STAFF

Updated 4:29 pm, Friday, June 3, 2011

Photo: WSDOT

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The first section (the red section above) of the Alaskan Way Viaduct is to be demolished in October. The bright green section represents the construction area, while the yellow part is the staging area. A: SR 99 closed for nine days while section of viaduct demolished; B: Northbound SR 99 on-ramp remains open during this period; C: Complete connection between permanent SR 99 lates and detour; D: Southbound SR 99 detour off-ramp to S. Atlantic Street complete.

The first section (the red section above) of the Alaskan Way Viaduct is to be demolished in October. The bright green section represents the construction area, while the yellow part is the staging area. A: SR

Crews will begin demolishing the southern mile of the Alaskan Way Viaduct in October - six months ahead of schedule, state officials said Friday.

Traffic then will be shifted to a new highway taking shape adjacent to the 1950s-era viaduct.

Demolition of the southern mile will take about six months. Once demolition is complete, there will be room to finish construction of the new highway -- two side-by-side structures each carrying three lanes. The construction, all part of the $482 million Holgate-to-King Street project , will be completed by mid-2013.

Friday's news means the most vulnerable section of the viaduct will be removed sooner than expected, Gov. Chris Gregoire said during an afternoon news conference.

"By demolishing this section of the viaduct six months earlier, we will complete the project six months earlier," she said. "Importantly, throughout this process, we will keep traffic moving, which we know is very important to people in this area.

The southern mile will be torn down ahead of the waterfront portion through downtown, which the state plans to replace with a $1.9 billion deep-bore tunnel project. Tunnel construction, which can't begin until final approval by federal authorities, isn't expected to begin until later this year.

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State Route 99 will be closed for nine days in October so crews can demolish a 200-yard chunk of the viaduct around Royal Brougham Way and build a detour road from the new highway to the ramps that currently allow traffic onto the central viaduct, said Ron Paananen, administrator for the Alaskan Way Viaduct replacement project. That will allow traffic to continue to use the central viaduct until the tunnel opens in 2015 or 2016.

Crews then will build the other half of the new highway, which will eventually carry northbound lanes. The first section of the new highway to open eventually will be southbound-only. In the interim, traffic will be restricted to two lanes in both directions.

Crews also will build a new overcrossing at Atlantic Street to carry traffic over railroad tracks along Alaskan Way. To see an interactive simulation of what construction will look like, click here.

Seattle Mayor Mike McGinn opposes the tunnel replacement, saying it's too costly and that the city may have to pay any cost overruns because of a clause in the legislation that authorized the tunnel. McGinn prefers tearing the viaduct down and dispersing the 110,000 vehicles that take it each day on surface streets, augmented by enhanced transit and road improvements.

On Aug. 16 Seattle voters will weigh in on a referendum about one part of city-state tunnel agreements. While the referendum can't halt work on the tunnel, many see it as a symbolic expression of support or opposition.

Engineers say the nearly 60-year-old structure must come down because it was damaged in an earthquake 10 years ago.

State officials said the southern mile of the viaduct can be removed sooner than plan because the state transportation department and contractor Skanska USA Civil found ways to streamline the project schedule and save money. Skanska was awarded a $114 million contract to build the new highway, which was 25 percent below the engineer's original cost estimate.

Skanska will receive $2.6 million from the state to compensate for additional work to complete the demolition earlier than planned. The net savings will be approximately $900,000. WSDOT will also retire $500,000 in risk with this plan.